1. Field of the Invention
The present invention relates generally to an air purifier and, more particularly, to an air purifier which includes an electric dust collecting device that electrically charges dust particles in air and collects the charged dust particles.
2. Description of the Related Art
As is well known to those skilled in the art, an air purifier is used to provide purified clean air after dust, bacteria and contaminants in air are eliminated. The air purifier is provided with an electric dust collecting device to collect dust, etc. In the electric dust collecting device, dust particles electrically charged by corona discharge of an ionizer are collected by electrostatic attraction of a collector electrically charged to have a polarity opposite to a polarity of the charged dust particles.
FIG. 1 is a side sectional view of a conventional air purifier. As shown in FIG. 1, the conventional air purifier includes a pre-filter 102, an ionizer 104, a collector 106, a final filter 108, and a fan 110. The pre-filter 102 acts primarily to filter relatively large dust particles. The ionizer 104, which constitutes the electric dust collecting device along with the collector 106, functions to charge the dust particles electrically to bear a positive polarity by corona discharge between a discharge electrode unit 104b and ground electrode units 104a positioned at both sides of the discharge electrode 104b. The collector 106 has a plurality of horizontal partitions 106a bearing a negative polarity. When the positively charged dust particles flow between the horizontal partitions 106a of the collector 106, the dust particles are adsorbed to, and collected on, the negatively charged horizontal partitions by electrostatic attraction. The final filter 108 functions to filter fine dust or mold not filtered by the collector 106. The fan 10 circulates air by forcibly circulating air from the pre-filter 102 to the final filter 108.
In the above-described conventional air purifier, when the discharge electrode unit 104b and the ground electrode units 104a constituting the ionizer 104 are perpendicular to each other, the discharge occurs. However, if plate-shaped ground electrodes are used, discharge spaces are limited to very small spaces, so that some of dust particles, which quickly move along circulating air generated by the fan 110, may not be electrically charged. The dust particles not electrically charged in the ionizer 104 are not collected by the collector 106, so that the filtering burden of the final filter 108 positioned behind the electric dust collecting device is increased.